Automatically actuated braking system

ABSTRACT

The present invention concerns a process for externally actuating a brake system as well as a brake system suitable for this purpose. The object of the present invention is to ensure that the brake system is automatically set to a suitable actuation state on the basis of an appropriate sensor. However, any danger to the driver or accidental actuation of the brake should be prevented to as large an extent as possible.  
     Taking this into account, the present invention proposes that both the surroundings of the brake pedal and, if necessary, additional parameters (d,{dot over (d)}, v ref ) be monitored by means of a sensor unit ( 6, 10, 11 ). Then the brake pressure (p nom ) will be set automatically in an expedient manner in dependence of the individual parameters that were evaluated. Advantageous further embodiments include proposals for precharging the brake or braking slightly or automatically applying a higher brake pressure in dependence of the measuring results, in so far as this is reasonable with respect to road conditions and the driver&#39;s wishes as they were assumed by the system.

[0001] DE-PS 40 28 290 discloses that a maximum brake pressure can bebuilt up in dependence of the speed with which the brake pedal isdepressed so as to cause an optimal braking of the vehicle. However,since the stopping time is made up of a reflex time, a reaction time, abrake response time, and the actual braking time, it may take arelatively long period of time before the vehicle stops or reaches thedesired state of deceleration due to the reflex time, the remainingreaction time and the brake response time. In this connection, reflextime is understood to be the time that the driver needs to realize thathe has to decelerate. The reaction time is the time that it takes thedriver to remove his right foot from its current position (e.g. on thegas pedal) and to place it on the brake pedal. The brake response timedescribes the time until the driver initiates the braking procedure,i.e. until the vehicle actually begins to accelerate negatively, i.e. todecelerate. For this purpose, the brake pedal has to overcome a certainidle distance and suitable pressure has to be built up so that the brakepads are applied to the brake discs with sufficient force. The actualbraking time is the time that is then still needed to stop the vehicleor until the vehicle reaches the desired lower speed.

[0002] Consequently, it becomes evident that the object of DE-PS 40 28299 only causes the braking time to be reduced, since the brake isautomatically applied with optimal force. The previously known brakesystem presupposes, however, an automatically controlled brake force,since the optimal brake pressure is considerably affected by weather androad conditions (dry roadway, icy roadway). It is known from DE-GM8911963 that the brake system can be made to respond as soon as thedriver's right foot leaves the gas pedal to depress the brake pedal. Inthis way, considerable reaction time and brake response time are saved.However, this system calls for a separate manipulation by the driver tobring the vehicle into a state, in which the desired behavior actuallyoccurs. This manipulation can take the form of activating a switch witha foot (the left one) or hand. A disadvantage in this connection is thatthe driver has to intentionally move a switch in a dangerous situationin order to reduce the reaction time and brake response time.

[0003] From DE-OS 44 22 664 it is known that a signal can be transmittedto the brake system when the right foot moves very quickly from a firstposition to a second position, with such signal causing a brakingprocedure. In this respect, a change in the position of the foot isunderstood to be moving the foot from the gas pedal to the brake pedal.Although this does allow a considerable reduction in the reaction timein special cases, it must be taken into consideration that the positionof the foot frequently is not changed prior to a necessary braking, forexample when the vehicle is being braked on a downhill road without anyprior activation of the gas pedal. The same also holds true for controldevices that hold the vehicle speed constant without any activation ofthe gas pedal (Tempomat, Cruise Control). The above-mentioned knowndevice also does not ensure that a massive braking procedure is notinitiated when the driver quickly takes the foot from the gas pedal, forexample for changing gears, and comes into the vicinity of the brakepedal.

[0004] U.S. Pat. No. 3,726,369 proposes that the brake system beactivated automatically as soon as the driver's foot is taken from thegas pedal and placed on the brake pedal. For this purpose, two sensorsare provided which control the movement of the foot. In principle theobject of this document corresponds to the devices described in DE-OS 4422 664, wherein the latter device saves additional reaction time in thatthe driver's foot does not have to come into contact with the brakepedal for initiating a braking reaction, but that a braking reactionoccurs when a certain movement is detected in the vicinity of the brakepedal by an appropriate sensor.

[0005] Hence, the present invention proceeds from a type of processresulting from the preamble of claim 1 as well as a brake system of thetype according to claim 12. The object of the invention is to adapt theautomatically executed braking procedure as far as possible to thedangerous situation. In particular it should be prevented that aninappropriately strong braking procedure is initiated in a situationwhere this would result in far greater risks to the driver than thepossible benefits of an automatic braking. Thus, it is the intention ofthe invention to render the initiation of the braking procedureindependent of a previous activation of the gas pedal. Furthermore, itis the object of the invention to base the type and scope of actuationof the brake not only on one single procedure but to make it dependenton a combination of measured data and to adapt the automatic reaction ofthe brake to all of the measured data combined.

[0006] The purpose is achieved through the combination of featuresresulting from the characterizing part of claim 1. Hence, the inventionin principle consists of making the type and scope of the automaticactuation of the brake system dependent on the size of an individualmeasured value or a combination of different types of measured values.In this connection there are numerous possibilities of actuation. Forone the brake system may only be precharged, which means that althoughthe brake pressure is increased to such an extent that the brake padsare applied to the brake disc, no braking procedure is initiated, i.e.the speed of the vehicle is not reduced by the brake. Anotherpossibility would be initial braking, i.e. to apply the brake pads tothe brake disc with a defined brake force for a specified period oftime. The brake force needed for this purpose can be very low (e.g. 5 to20 bar can be applied), i.e. a pressure range that is handled during asudden change of pressure in a booster (jump-in function, jump-in value)(no ABS needed). Finally the optimal brake force can be applied to thebrake discs, i.e. the optimal pressure can be made availableautomatically in the brake system. However, this means that there has tobe a controlled brake system (ABS), since the optimal brake forcedepends significantly on the road conditions, the load carried by thevehicle and other factors, which can only be governed by an appropriatecontrol system. If such a control system is not available, thepreprogrammed automatic braking procedure must always only go so farthat it doesn't result in any danger to the vehicle, also not underunfavorable conditions. Naturally it is possible to program or, ifnecessary, adapt the vehicle to seasons or the area where the vehicle isdriven, since, for example, icy roadways are highly unlikely duringcertain times of the year or in certain regions. Hence, application ofthe combination of features according to claim 2 is recommended.

[0007] Based on the information provided above, it is evident that thetype of actuation of the brake system not only should be uncritical butalso should prevent any accidental actuation of the automatic brakingprocedure as far as possible. In this respect the combination offeatures according to claim 3 is recommended. On the one hand thisensures that an initiation of braking procedures is improbable when itis not actually intended (does not depend on depression of the gaspedal); on the other hand a considerable amount of reaction time issaved by already actuating the brake system whenever it can be expectedwith a high degree of probability that the driver will want to brake.Finally, the chronological sequence of the change of position above thebrake pedal (speed of change or foot acceleration) can indicate howstrongly the driver wants to brake. When the driver's foot acceleratesvery quickly or the speed of movement towards the brake pedal is veryfast, it can be assumed that the driver actually wants a strong brakingprocedure. This is also correct in view of the fact that he would put onthe brakes strongly anyway, since he couldn't stop or pull back his footin time. Yet, the type of brake actuation in this case could also bemade dependent on the distance between the driver's foot and the surfaceof the brake pedal. If the acceleration or foot speed occurs at a largedistance from the brake pedal, then it would not seem appropriate toinitiate a strong braking procedure at this time (initial braking). Inthis case, precharging the brake would suffice, i.e. making the brakepads slide lightly on the brake discs, since thereby the idle path ofthe pedal is obviated and, hence, the required braking distance isreduced. Thus, this type of actuation would only give rise to adifferent feeling of confirmation on the brake pedal for the driver.However, the vehicle is not jerked by the initial braking and the brakelinings are not subjected to unnecessary wear. For this purpose, thebrake system can be designed in such a way that the brake pedalautomatically moves towards the braking position. As a result, the footneed depress the pedal only a short distance and can exert only aninsignificant amount of force in order to actuate a force sensor.

[0008] However, in order to also help the driver when he has placed hisfoot on the brake pedal, the combination of features proposed in afurther embodiment of the invention according to claim 4 is recommended.In this case, brake pedal refers to any kind of brake actuation elementthat triggers a corresponding braking procedure whenever a force isapplied, either by depressing the pedal or applying force. A forcesensor is not necessarily needed for this purpose. Nonetheless such aforce sensor may prove very expedient in brake systems with specialcontrol devices, particularly when these systems do not include measuresfor detecting the brake pressure or the actuating path and if thedriver's foot can depress the pedal only a very short distance.

[0009] As was already discussed above, application of the combination offeatures according to claim 5 is very appropriate since it cansignificantly adapt the actuation of the brake system to the detectedrequirements of the driver. The objective is to achieve as high abraking effect as possible without endangering or disturbing the driver.Claim 5 in particular describes the possibility of adapting the strengthof the braking procedure to the speed or the acceleration of the footmovement. The strength of the braking procedure can additionally orexclusively be rendered dependent on the force with which the foot isapplied to the brake pedal. Hence, the present invention provides apossibility of making the strength of the braking dependent on severalparameters. This can include exclusively, but also additionally, thatthe strength of the braking procedure be made dependent on a safetysignal that takes into consideration ambient dangers, wherein saidsafety signal could be determined by the distance to the vehicle aheadof one's own vehicle, one's own vehicle speed and the relative speedbetween the two vehicles. In addition, when there is a controlled brakesystem (ABS), its control behavior can be used. In this case it ispossible to automatically apply the full brake pressure on the brakewhen it is detected that the driver wants to brake strongly or when astrong braking is necessary due to a danger signal, and the controlsystem of the brake system can help compensate any difficulties arisingin connection with the condition of the roadway surface.

[0010] An expedient combination of the above-mentioned possibilities isprovided in the combination of features according to claim 6. In thisconnection it needs to be underscored once again that only prechargingor light initial braking should be strived for in uncontrolled brakesystems, as occurs, for example, with the jump-in function of a booster.

[0011] The strategy is to actuate the brake system as appropriately aspossible in accordance with the braking needs of the driver as detectedthrough the measured signals, taking into consideration any possibledanger to the driver. The combination of features according to claim 7describes preferred options when the driver already has placed his footon the pedal and is applying pressure to the pedal. Whereas the systemcannot determine precisely whether or how strongly the driver wants tobrake while the foot is still above the brake pedal, the desire to brakeis quite clear in the case described by the combination of featuresaccording to claim 7, and the speed as well as the acceleration of thefoot movement can be taken as the measure for the desired brake force.Naturally this presupposes that the brake system still allows the pedalto be depressed a significant distance when the foot is placed on thepedal (e.g. when the foot is placed on the pedal very slowly).

[0012] The combination of features according to claim 8 describes thisin more detail. It should be taken into consideration, however, thathere, too, the value of the safety signal with respect to the vehicle infront can be included, i.e. also irrespective of the position ormovement of the foot above or on the brake pedal.

[0013] A particularly expedient system is described by the combinationof features according to claim 9. According to this embodiment, severalsignals measured parallel to one another can be linked. If, for example,such a measurement determines that the driver's desire to brake iscomparably weak because his foot is resting above the brake pedal and asafety signal indicating a vehicle in front is emitted at the same time,these two values can be united and a need for a higher brake force willbe determined. The same thing applies when the values combined to formthe safety signal are viewed individually, i.e. the vehicle's own speed,the relative speed and the distance to the vehicle in front. In thiscase, the values could also be assigned to individually determined brakepressure values, which are then combined and result in the conclusionthat a higher brake force is needed. Correspondingly a weak dangersignal alone can be used to precharge the brake system or to initiatelight initial braking.

[0014] These types of combinations of features are described in claims10 and 11.

[0015] A brake system particularly well-suited for carrying out theprocess proposed by the present invention is described by thecombination of features according to claim 12, wherein a first sensordevice is not limited to monitoring and measuring the movement of thebrake pedal proper and/or the movement of the foot above the brakepedal. The sensor can be an infrared sensor that measures the distancebetween the foot and the sensor by means of an infrared ray. The sensorcan be capacitive, too, in that it also determines the field changes(deviating field resistance of the foot) resulting from the movement ofthe driver's foot. Another possibility would be to use Hall probes tomeasure at least the distance or the movement of the pedals. In the sameway, optical sensors or ultrasonic sensors could be used. As mentionedbefore, the important point is that the form of the automatic actuation,i.e. precharging, slight initial braking, strong initial braking or afull braking according to the driver's wish, should always depend on thevalue of one or several measuring results.

[0016] A particularly simple sensor arrangement is proposed by thecombination of features according to claim 13, wherein the sensor itselfis protected by the pedal, but can monitor the space above the pedalthrough an opening, through which, for example, it can radiate infraredor optical signals. The further embodiment of the invention proposed bythe combination of features according to claim 14 is recommended if onewants to avoid having a single sensor, which can, for example, bemounted somewhere on the splashboard, monitor both the movement of thefoot and the movement of the pedals. The advantage offered by thisembodiment is that the measured signals can be unequivocally assigned toa foot above the pedal and a foot on the pedal. Moreover, this makes itpossible to adjust the system more easily and accurately, because it isknown that the first sensor measures the distance between the foot andthe pedal at height 0 when the second sensor determines the beginning ofa movement of the pedal.

[0017] A force sensor may be included exclusively or additionally in thefirst sensor device as proposed by the combination of features accordingto claim 15. In particular, this would allow controlled brake systems,whose control also depends on the pedal force exerted by, the driver, tobe actuated comparably easily. This would lead to a considerablesimplification of the control system as well as corresponding costreductions. The force sensor can be mounted in the path of forcetransmission leading to the inside of the booster. It can, for example,be a piezoelectric sensor on the surface of the pedal, a force sensor inthe piston rod or in a force-transmitting joint.

[0018] The safety signal mentioned above can be obtained by means of thecombination of features described in claim 16, wherein several inputvalues are linked in an appropriate manner.

[0019] For this purpose, an arithmetic unit according to claim 17 can,for example, be used, which appropriately evaluates and weights theindividual danger parameters. A corresponding arithmetic unit can alsobe used in connection with the arithmetic units applied for the driver'sfoot and the brake pedal according to the combination of featuresdescribed in claim 18.

[0020] Thus, it is quite appropriate for the brake system to apply thefeatures according to claim 19, wherein the values provided by theindividual arithmetic units are linked with each other appropriately ina coordinating unit, giving rise to a suitable value that determines thebrake pressure to be set automatically.

[0021] With respect to the brake system described herein, it isparticularly expedient to provide a brake pressure transducer accordingto claim 20, which can be actuated independently of the driver's foot(independent assist actuation) and, hence, determines the required typeand extent of actuation (e.g. booster, pump, pressure accumulator.

[0022] An exemplary embodiment of the invention is explained on thebasis of the following drawings:

[0023]FIG. 1 shows a brake pedal with sensors according to the presentinvention;

[0024]FIG. 2 is a symbolic top-view representation of the brake pedalaccording to FIG. 1; and

[0025]FIG. 3 shows how several signals indicating the required brakepressure are linked to activate a brake pressure transducer.

[0026] In FIG. 1 the inside surface of a vehicle in the vicinity of thebrake pedal is shown. This is limited by the splashboard 1, which isfixed in relation to the body of the vehicle. The brake lever 3 issuspended on the splashboard 1 or on another part that is fixed on thevehicle by means of a bearing 2. The brake lever 3 has a brake pedal 4,and both parts are connected to one another in one piece. There is anopening 5 in the brake pedal 4, at whose left end (please refer toFIG. 1) a first sensor 6 is mounted. Said sensor can be an infraredsensor, an ultrasonic sensor, an optical sensor, a capacitive sensor oranother suitable sensor. The sensor radiates a field 7, which, insimplified terms, is approximately ball-shaped. At the same time, thesensor is equipped with a measuring device (not shown), which is used tomeasure the distance A of the bottom shoe sole 8 of the foot 9. Not onlydistance A but also the speed {dot over (A)} and the acceleration Ä ofthe foot in relation to a reference point can be determined by means ofsuitable evaluation and/or calculation devices (not shown). The surfaceof the brake pedal 4 is given preference as the reference point. Thesevalues can be used to determine what type and form of brake actuation isrequired. For this purpose, the sensor can also be mounted at anotherplace in the floor area, for example on the splashboard below the brakepedal 4.

[0027] A capacitive sensor can preferably be used as the first sensor.For this purpose, electrodes having a capacitive effect on one anotherare mounted on the side of the brake pedal 4 facing towards the foot 9.These electrodes can be two large capacitive areas basically arranged onone level at a certain distance from each other. The surfaces could alsobe curled together like a spiral. A measuring frequency is applied tothe capacitor formed in this way. The approaching foot causes the field(capacity) to be detuned since its relative permittivity deviates fromthe surroundings, making it possible to measure the foot's speed ofapproach.

[0028] Another possibility would be to use an ultrasonic sensor. Itsmembrane should be positioned in such a way that it ends approximatelyat the opening's 5 limiting edge that faces towards the foot, so thatthe ultrasonic transformer is fitted in the opening. In FIG. 1 a secondsensor 10, which also is a position sensor, is indicated on the leftbottom side of the pedal 4 (see FIG. 1). This position sensor measuresthe path traveled by the pedal 4 as soon as the foot 9 touches the pedal4. For this purpose, said position sensor does not have to be mounted onthe bottom side of the pedal with its direction of measurement facingtowards the splashboard 1. It will suffice if it is mounted at anappropriate position, from where it can measure either directly orindirectly the path traveled by the pedal 4. It can, for example, alsobe mounted at a suitable place on the brake lever 3 or on the piston rod21 connected to the brake lever via a joint 20, which leads to a boosterthat is not shown. Hence, the path traveled by the pedal 10 can also bemeasured within the booster. Thus, the sensor 10 describes the action ofthe foot on the pedal, and an appropriate brake pressure can be setautomatically in the brake system depending on the path traveled by thepedal B or the pedal speed {dot over (B)} or the pedal acceleration{umlaut over (B)}. However, it also appears possible to have thefunctions of sensors 6 and 10 be carried out by one single sensor,which, for example, monitors the distance, any change in distance or theacceleration of the bottom surface of the foot, irrespective of whetherthe foot touches the pedal 4 or not.

[0029] Since, in the present invention, the brake already is actuated ina suitable manner as soon as the foot 9 approaches the pedal 4, thebrake system according to the present invention is outstandinglysuitable for determining the brake pressure with the aid of a forcesensor when the foot touches the pedal. Since the brake already hasautomatically overcome the customary idle path before the foot 9 touchesthe pedal 4, the foot depresses the pedal only negligibly smalldistances, whereas the brake pressure in the brake system is almostexclusively determined by the force exerted by the driver's foot.Consequently, the position sensor 10 will not be necessary and can bereplaced by the force sensor 11, which is symbolically integrated in thepiston rod 21 in FIG. 1. Naturally the force sensor 11 can be used inaddition to the position sensor 10.

[0030]FIG. 2 is a top view of the brake pedal 4 with the opening 5 aswell as the indicated spherical (preferably essentially ball-shaped)measuring field 7. The sensor mounted in the opening can be held by websrunning, radially from the edge of the opening, so that dirt can falloff between the webs.

[0031] Three arithmetic units 15, 16, 22 are shown in FIG. 3. A seriesof values measured by a second sensor device, which describe the dangerof the vehicle colliding with a vehicle in front, are input into thearithmetic unit 15. These values are the distance d to the vehicle infront, the change in distance per time unit {dot over (d)}, the speed ofone's own vehicle V_(Ref), and T, a defined time that describes thedesired safety time up to a collision. These data are linked in thearithmetic unit, which has at its disposal tables that describe thebrake pressure to be set on the basis of the distance, d, {dot over(d)}, v_(Ref), T as well as other parameters, if necessary. In this way,the desired brake pressure p1 can be determined.

[0032] On the basis of the distance A or B and/or {dot over (A)}, Ä or{dot over (B)},{umlaut over (B)}, the arithmetic unit 16 determines asuitable brake pressure p2 that is to be applied in the brake system. Inthe third arithmetic unit 22, a value corresponding to the foot force Fis provided. Due to the logically linked parameters, a suitable brakepressure p3 can be determined from this by means of the tables containedin arithmetic unit 22. Of significant importance in the presentinvention is the coordinator 17, which determines a coordinated pressurevalue based on the output vales p1, p2, p3, each of which individuallydescribes an appropriate pressure that is to be applied by the brakesystem. As a rule, this coordinated pressure value will be larger thaneach of the three individual pressure values p1, p2, p3. It can, forexample, be made up of the sum of the three pressure values p1, p2, p3.It can, however, also be a maximum pressure value that is formed as afunction of p1, p2, p3, which lies far below the sum of the individualpressure values p1, p2, p3. The resulting pressure P_(nom) is suppliedto a brake pressure transducer that is actuated accordingly. Said brakepressure transducer, for example, can consist of an active booster thatcan be actuated externally, it can also be a pressure fluid storageunit, a pressure fluid pump, a hydraulic amplifier. The active boosteris additionally actuated in the manner customarily used by means of asignal P_(H), which corresponds to the actual value of the pressure inthe main cylinder and serves to close the control loop. A prechargingcondition accompanied by a corresponding P_(nom) can be maintained inthe brake system even though the driver releases the pedal.

[0033] Therefore, the following can be stated in particular: A systemthat was already proposed includes a control system for the longitudinaldynamics, which is provided for controlling processes of longitudinaldynamics exceeding the limit range (ABS/ASC function).

[0034] The task of the control unit is to unite such functions asautomatic speed control, collision avoidance control (following avehicle driving in front) and other control functions with respect tolongitudinal dynamics as well as to supply these as effectively aspossible to the actuators (brake, gearbox, engine) in case of a brakingprocedure with a certain limited deceleration. In the same way, theinterface to the driver has to be maintained and state values (speed,distance, force, etc.) have to be input and output.

[0035] Control systems proposed up until now have always proceeded onthe assumption that the control unit is no longer active when the driverintervenes (switching off the ICC system, stepping on the brake) and,consequently, cannot initiate any braking to support the driver.However, control systems aiming for collision avoidance, some of whichare always active and also permit braking procedures with a greaterdeceleration, exhibit the disadvantage that an erroneous detection maygive rise to a full braking procedure.

[0036] Studies have shown that brake systems with a certain degree offilling (precharged brake system with 5-10 bar pressure) carry out thesubsequent driver-initiated braking quicker and with less scatter. Thus,braking distance is gained. In the same way research has shown that afull braking procedure (for a certain time T until the driver takesover) initiated when movement of the driver's foot is detected, i.e.from the gas pedal to the brake pedal, can reduce the braking distance,but also can give rise to great risks and cause the driver to beirritated by erroneous brake actuation.

[0037] It is proposed herein that determination of the distance/therelative speed in respect to a vehicle in front by means of a distancesensor and/or detection of the driver's foot approaching the brake pedalbe used to precharge the vehicle's brake. Fulfillment of one of the twoconditions (short distance/high relative speed, foot movement) alonewill not result in a marked deceleration of the vehicle. Nevertheless,the brake system will be pre-applied and, hence, critical time that thedriver normally needs for this procedure will be saved. The fulfillmentof both conditions makes a large precharging of the brakes expedient,since it can be expected with some certainty that the driver will brake.

[0038] When the driver's foot approaches the brake pedal, a sensordetermines the distance between the foot and the pedal. As soon as acertain threshold is crossed, a precharge pressure p₂ is generated. Thiscan remain constant as the driver's foot continues to approach the brakepedal, but can change as a function of the distance and the change inthe distance. The pressure determined is supplied to the brake system bymeans of an active booster.

[0039] However, precharging can also be caused by insufficient distanceand/or high speed of one's own vehicle, in which case the distancesensor determines the distance and the chronological derivation of thedistance (relative speed) to a vehicle driving in front. The safetydistance is composed of a time T (time to collision) and the vehicle'sown speed v_(ref). The data provided by the sensor can be used to obtainan approximate calculation of the acceleration of the vehicle driving infront {dot over (v)}₁. The decision whether precharging is to beinitiated and the extent of such precharging p₁ is made on the basis ofthe sensor data in relation to the safety distance and the vehicle's ownspeed. A criterion in this connection can be exceeding a limit value (orsafety value) such as, for example,${d = {{T*v_{ref}} - \frac{v_{ref}^{2}}{2*{\overset{.}{v}}_{ref}} + \frac{v_{1}^{2}}{2 + {\overset{.}{v}}_{1}}}},$

[0040] where the pressure value p₁ can be a function of the degree thatthe limit value is exceeded. In this connection, v₁ is the speed of thevehicle in front and {dot over (v)}₁ is its acceleration. The limitvalue can be formed by curves determined by experiment.

[0041] Both requirements posed with respect to precharging are combinedvia a coordinator function. Said coordinator function can consist offorming the sum total of both pressure values, a maximum function orother operators.

1. A process for actuating the brake system of a vehicle with the helpof the driver's foot (9), wherein said brake system is equipped with abrake actuating element, in particular brake pedals (4), characterizedin that a sensor device (6,10) located in the vicinity (7) of the brakepedal (4) measures the position (A, B) and/or change of position ({dotover (A)}, Ä, {dot over (B)}, {umlaut over (B)}) of the foot or thepedal and/or the force (11) exerted by the foot (9) on the brakeactuating element and/or a safety value (d, {dot over (d)}, v_(ref))defined on the basis of a vehicle driving in front, and an evaluationunit compares the measured state with at least one defined state andactuates the brake system depending on the result of the comparison. 2.A process according to claim 1, characterized in that the evaluationunit compares the result of the measurement with one or several definedstates and that the type of actuation of the brake system depends on theresult of the comparison.
 3. A process according to claim 1 or 2,characterized in that the position (A) and/or change of position ({dotover (A)},Ä) of the foot (9) is measured above the brake actuating unit(4), in particular the brake pedal.
 4. A process according to one of theclaims 1 to 3, characterized in that the position (B) and/or the changeof position ({dot over (B)}, {umlaut over (B)}) of the foot (9) standingon the brake actuating unit (4) and/or the force (F) exerted by the footon the brake actuating unit are measured.
 5. A process according to oneof the preceding claims, characterized in that the actuation of thebrake system depends on the measuring result or the measuring resultsduring precharging, initial braking, adjustment of an appropriate brakepressure or application of the maximum brake pressure.
 6. A processaccording to one of the preceding claims, characterized in thatprecharging or initial braking occurs in the brake system as soon as thedistance (A) between the foot and the brake actuating unit (4) fallsbelow a first specified distance value and/or the speed of movement({dot over (A)}) towards the pedal and/or acceleration (Ä) exceeds acorresponding specified value and/or the safety value measured (d, {dotover (d)}, v_(ref)) has reached a sufficiently high value.
 7. A processaccording to one of the claims 1 to 6, characterized in that the brakesystem is initially braked or brought to full brake force when the foot(9) is in contact with the brake pedal (4) and the speed of movement({dot over (B)}) towards the floor panel (1) and/or acceleration({umlaut over (B)}) and/or the force of the foot (9) exceeds acorresponding specified value.
 8. A process according to one of thepreceding claims, characterized in that the brake force set in the brakesystem depends on the speed measured ({dot over (A)}, {dot over (B)})and/or acceleration (Ä, {umlaut over (B)}) of the foot or the pedal (9).9. A process according to one of the preceding claims, characterized inthat the braking pressure (P_(nom)) of the brake system is increasedappropriately as a function of several values determined parallel to oneanother (p1, p2, p3).
 10. A process according to claim 9, characterizedin that certain brake pressures (p1, p2, p3) are assigned to individual,generically different measured values (d, {dot over (d)}, v_(ref) or A,B, F) and that when these measured values occur parallel in the brakesystem the brake pressures are added or their maximum is formed.
 11. Aprocess according to one of the preceding claims, characterized in thatthe safety signal (p1) supplied by a second sensor device (d, {dot over(d)}, v_(ref)) is derived from the speed (v_(ref)) and/or the vehicle'sown acceleration ({dot over (v)}_(ref)) and/or the distance (d) and/orthe relative speed ({dot over (d)}) with respect to a vehicle driving infront and/or the acceleration of a vehicle driving in front ({dot over(v)}₁).
 12. A brake system with a brake actuating element, in particulara brake pedal (4), also for carrying out the processes according toclaims 1 to 11, characterized in that at least a first sensor unit (6,10) is provided to monitor the position (A, B) and/or the change inposition ({dot over (A)}, {dot over (B)}) of the foot (9) located aboveor on the pedal, and an evaluation unit actuates the brake system on thebasis of the measuring results, wherein the type and extent of actuationdepends on the measuring results.
 13. A brake system according to claim12, characterized in that a first sensor (6), preferably an infraredsensor, is assigned to the first sensor unit (6, 10) on the brake pedal,that the sensor preferably is mounted somewhere on the pedal surfacefacing away from the foot (9) and monitors the area (7) of the pedalfacing towards the foot through an opening (5) in the pedal (4), that afirst sensor of the sensor unit, preferably a capacitive sensor, ismounted on the surface of the pedal facing towards the foot or that afirst sensor of the sensor unit, preferably an infrared sensor, isintegrated in a corresponding opening in the pedal.
 14. A brake systemaccording to claim 13, characterized in that a second sensor (10) isprovided in the first sensor unit, wherein said second sensor monitorsthe distance (B) and/or the change in distance ({umlaut over (B)}) ofthe pedal with respect to a reference point.
 15. A brake systemaccording to one of the claims 12 to 14, characterized in that a forcesensor (11) is provided in the first sensor unit (6, 10, 11), whichmeasures the force exerted on the brake pedal (4) by the foot (9).
 16. Abrake system according to one of the claims 12 to 15, characterized inthat an additional sensor unit (d, {dot over (d)}, v_(ref)) is providedto measure the speed (v_(ref)) of the vehicle and/or the distance (d)and/or the relative speed ({dot over (d)}) with respect to a vehicledriving in front and/or an evaluation unit to calculate the vehicle'sown acceleration ({dot over (v)}_(ref)) and the acceleration of thevehicle driving in front ({dot over (v)}₁ _().)
 17. A brake systemaccording to claim 16, characterized in that a first arithmetic unit(15) is provided, which determines the brake pressure (p1) to beactuated on the basis of a specified safety time (T), the vehicle's ownspeed (v_(ref)) and/or the vehicle's own acceleration ({dot over(v)}_(ref)) and/or the relative speed ({dot over (d)}) and/or thedistance (d) to a vehicle driving in front and/or its acceleration ({dotover (v)}₁).
 18. A brake system according to one of the claims 12 to 17,characterized in that said brake system is equipped with a secondarithmetic unit (16) which determines the brake pressure (p2) to beactuated on the basis of the distance (A) between the foot (9) and thebrake pedal (4) and/or the pedal path (8), and/or that a thirdarithmetic unit is provided, which determines the brake pressure (p3) tobe actuated on the basis of the foot force measured.
 19. A brake systemaccording to claim 18, characterized in that a coordination unit (17) isprovided, which determines an appropriate brake pressure (P_(nom)) basedon the values output by the arithmetic units (15, 16, p1, p2, p3).
 20. Abrake system according to one of the claims 12 to 15, characterized inthat a brake pressure transducer (20) which can be actuatedindependently of the foot's actions, preferably a booster, is provided,wherein said brake pressure transducer supplies the brake pressure thatis to be applied in accordance with the output signals of thecoordinator (17) and/or the arithmetic units and/or the evaluation unit.